file.c

   1 /*
   2  * libuci - Library for the Unified Configuration Interface
   3  * Copyright (C) 2008 Felix Fietkau <nbd@openwrt.org>
   4  *
   5  * this program is free software; you can redistribute it and/or modify
   6  * it under the terms of the gnu lesser general public license version 2.1
   7  * as published by the free software foundation
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  */
  14
  15 /*
  16  * This file contains the code for parsing uci config files
  17  */
  18
  19 #include <sys/types.h>
  20 #include <sys/stat.h>
  21 #include <stdbool.h>
  22 #include <stdio.h>
  23 #include <ctype.h>
  24
  25 #define LINEBUF 32
  26 #define LINEBUF_MAX     4096
  27
  28 /*
  29  * Fetch a new line from the input stream and resize buffer if necessary
  30  */
  31 static void uci_getln(struct uci_context *ctx, int offset)
  32 {
  33         struct uci_parse_context *pctx = ctx->pctx;
  34         char *p;
  35         int ofs;
  36
  37         if (pctx->buf == NULL) {
  38                 pctx->buf = uci_malloc(ctx, LINEBUF);
  39                 pctx->bufsz = LINEBUF;
  40         }
  41
  42         ofs = offset;
  43         do {
  44                 p = &pctx->buf[ofs];
  45                 p[ofs] = 0;
  46
  47                 p = fgets(p, pctx->bufsz - ofs, pctx->file);
  48                 if (!p || !*p)
  49                         return;
  50
  51                 ofs += strlen(p);
  52                 if (pctx->buf[ofs - 1] == '\n') {
  53                         pctx->line++;
  54                         pctx->buf[ofs - 1] = 0;
  55                         return;
  56                 }
  57
  58                 if (pctx->bufsz > LINEBUF_MAX/2) {
  59                         pctx->reason = "line too long";
  60                         pctx->byte = LINEBUF_MAX;
  61                         UCI_THROW(ctx, UCI_ERR_PARSE);
  62                 }
  63
  64                 pctx->bufsz *= 2;
  65                 pctx->buf = uci_realloc(ctx, pctx->buf, pctx->bufsz);
  66         } while (1);
  67 }
  68
  69 /*
  70  * Clean up all extra memory used by the parser and exporter
  71  */
  72 static void uci_file_cleanup(struct uci_context *ctx)
  73 {
  74         struct uci_parse_context *pctx;
  75
  76         if (ctx->buf) {
  77                 free(ctx->buf);
  78                 ctx->buf = NULL;
  79                 ctx->bufsz = 0;
  80         }
  81
  82         pctx = ctx->pctx;
  83         if (!pctx)
  84                 return;
  85
  86         ctx->pctx = NULL;
  87         if (pctx->package) {
  88                 uci_list_del(&pctx->package->list);
  89                 uci_drop_config(pctx->package);
  90         }
  91         if (pctx->buf)
  92                 free(pctx->buf);
  93         if (pctx->file)
  94                 fclose(pctx->file);
  95
  96         free(pctx);
  97 }
  98
  99 /*
 100  * parse a character escaped by '\'
 101  * returns true if the escaped character is to be parsed
 102  * returns false if the escaped character is to be ignored
 103  */
 104 static inline bool parse_backslash(struct uci_context *ctx, char **str)
 105 {
 106         /* skip backslash */
 107         *str += 1;
 108
 109         /* undecoded backslash at the end of line, fetch the next line */
 110         if (!**str) {
 111                 *str += 1;
 112                 uci_getln(ctx, *str - ctx->pctx->buf);
 113                 return false;
 114         }
 115
 116         /* FIXME: decode escaped char, necessary? */
 117         return true;
 118 }
 119
 120 /*
 121  * move the string pointer forward until a non-whitespace character or
 122  * EOL is reached
 123  */
 124 static void skip_whitespace(struct uci_context *ctx, char **str)
 125 {
 126 restart:
 127         while (**str && isspace(**str))
 128                 *str += 1;
 129
 130         if (**str == '\\') {
 131                 if (!parse_backslash(ctx, str))
 132                         goto restart;
 133         }
 134 }
 135
 136 static inline void addc(char **dest, char **src)
 137 {
 138         **dest = **src;
 139         *dest += 1;
 140         *src += 1;
 141 }
 142
 143 /*
 144  * parse a double quoted string argument from the command line
 145  */
 146 static void parse_double_quote(struct uci_context *ctx, char **str, char **target)
 147 {
 148         char c;
 149
 150         /* skip quote character */
 151         *str += 1;
 152
 153         while ((c = **str)) {
 154                 switch(c) {
 155                 case '"':
 156                         **target = 0;
 157                         *str += 1;
 158                         return;
 159                 case '\\':
 160                         if (!parse_backslash(ctx, str))
 161                                 continue;
 162                         /* fall through */
 163                 default:
 164                         addc(target, str);
 165                         break;
 166                 }
 167         }
 168         ctx->pctx->reason = "unterminated \"";
 169         ctx->pctx->byte = *str - ctx->pctx->buf;
 170         UCI_THROW(ctx, UCI_ERR_PARSE);
 171 }
 172
 173 /*
 174  * parse a single quoted string argument from the command line
 175  */
 176 static void parse_single_quote(struct uci_context *ctx, char **str, char **target)
 177 {
 178         char c;
 179         /* skip quote character */
 180         *str += 1;
 181
 182         while ((c = **str)) {
 183                 switch(c) {
 184                 case '\'':
 185                         **target = 0;
 186                         *str += 1;
 187                         return;
 188                 default:
 189                         addc(target, str);
 190                 }
 191         }
 192         ctx->pctx->reason = "unterminated '";
 193         ctx->pctx->byte = *str - ctx->pctx->buf;
 194         UCI_THROW(ctx, UCI_ERR_PARSE);
 195 }
 196
 197 /*
 198  * parse a string from the command line and detect the quoting style
 199  */
 200 static void parse_str(struct uci_context *ctx, char **str, char **target)
 201 {
 202         do {
 203                 switch(**str) {
 204                 case '\'':
 205                         parse_single_quote(ctx, str, target);
 206                         break;
 207                 case '"':
 208                         parse_double_quote(ctx, str, target);
 209                         break;
 210                 case 0:
 211                         goto done;
 212                 case '\\':
 213                         if (!parse_backslash(ctx, str))
 214                                 continue;
 215                         /* fall through */
 216                 default:
 217                         addc(target, str);
 218                         break;
 219                 }
 220         } while (**str && !isspace(**str));
 221 done:
 222
 223         /*
 224          * if the string was unquoted and we've stopped at a whitespace
 225          * character, skip to the next one, because the whitespace will
 226          * be overwritten by a null byte here
 227          */
 228         if (**str)
 229                 *str += 1;
 230
 231         /* terminate the parsed string */
 232         **target = 0;
 233 }
 234
 235 /*
 236  * extract the next argument from the command line
 237  */
 238 static char *next_arg(struct uci_context *ctx, char **str, bool required)
 239 {
 240         char *val;
 241         char *ptr;
 242
 243         val = ptr = *str;
 244         skip_whitespace(ctx, str);
 245         parse_str(ctx, str, &ptr);
 246         if (required && !*val) {
 247                 ctx->pctx->reason = "insufficient arguments";
 248                 ctx->pctx->byte = *str - ctx->pctx->buf;
 249                 UCI_THROW(ctx, UCI_ERR_PARSE);
 250         }
 251
 252         return uci_strdup(ctx, val);
 253 }
 254
 255 /*
 256  * verify that the end of the line or command is reached.
 257  * throw an error if extra arguments are given on the command line
 258  */
 259 static void assert_eol(struct uci_context *ctx, char **str)
 260 {
 261         char *tmp;
 262
 263         tmp = next_arg(ctx, str, false);
 264         if (tmp && *tmp) {
 265                 ctx->pctx->reason = "too many arguments";
 266                 ctx->pctx->byte = tmp - ctx->pctx->buf;
 267                 UCI_THROW(ctx, UCI_ERR_PARSE);
 268         }
 269 }
 270
 271 /*
 272  * switch to a different config, either triggered by uci_load, or by a
 273  * 'package <...>' statement in the import file
 274  */
 275 static void uci_switch_config(struct uci_context *ctx)
 276 {
 277         struct uci_parse_context *pctx;
 278         const char *name;
 279
 280         pctx = ctx->pctx;
 281         name = pctx->name;
 282
 283         /* add the last config to main config file list */
 284         if (pctx->package) {
 285                 uci_list_add(&ctx->root, &pctx->package->list);
 286
 287                 pctx->package = NULL;
 288                 pctx->section = NULL;
 289         }
 290
 291         if (!name)
 292                 return;
 293
 294         /*
 295          * if an older config under the same name exists, unload it
 296          * ignore errors here, e.g. if the config was not found
 297          */
 298         UCI_TRAP_SAVE(ctx, ignore);
 299         uci_unload(ctx, name);
 300         UCI_TRAP_RESTORE(ctx);
 301 ignore:
 302         ctx->errno = 0;
 303
 304         pctx->package = uci_alloc_config(ctx, name);
 305 }
 306
 307 /*
 308  * parse the 'package' uci command (next config package)
 309  */
 310 static void uci_parse_package(struct uci_context *ctx, char **str)
 311 {
 312         char *name = NULL;
 313
 314         /* command string null-terminated by strtok */
 315         *str += strlen(*str) + 1;
 316
 317         UCI_TRAP_SAVE(ctx, error);
 318         name = next_arg(ctx, str, true);
 319         assert_eol(ctx, str);
 320         ctx->pctx->name = name;
 321         uci_switch_config(ctx);
 322         UCI_TRAP_RESTORE(ctx);
 323         return;
 324
 325 error:
 326         if (name)
 327                 free(name);
 328         UCI_THROW(ctx, ctx->errno);
 329 }
 330
 331 /*
 332  * parse the 'config' uci command (open a section)
 333  */
 334 static void uci_parse_config(struct uci_context *ctx, char **str)
 335 {
 336         char *name = NULL;
 337         char *type = NULL;
 338
 339         if (!ctx->pctx->package) {
 340                 if (!ctx->pctx->name) {
 341                         ctx->pctx->byte = *str - ctx->pctx->buf;
 342                         ctx->pctx->reason = "attempting to import a file without a package name";
 343                         UCI_THROW(ctx, UCI_ERR_PARSE);
 344                 }
 345                 uci_switch_config(ctx);
 346         }
 347
 348         /* command string null-terminated by strtok */
 349         *str += strlen(*str) + 1;
 350
 351         UCI_TRAP_SAVE(ctx, error);
 352         type = next_arg(ctx, str, true);
 353         name = next_arg(ctx, str, false);
 354         assert_eol(ctx, str);
 355         ctx->pctx->section = uci_add_section(ctx->pctx->package, type, name);
 356         UCI_TRAP_RESTORE(ctx);
 357         return;
 358
 359 error:
 360         if (name)
 361                 free(name);
 362         if (type)
 363                 free(type);
 364         UCI_THROW(ctx, ctx->errno);
 365 }
 366
 367 /*
 368  * parse the 'option' uci command (open a value)
 369  */
 370 static void uci_parse_option(struct uci_context *ctx, char **str)
 371 {
 372         char *name = NULL;
 373         char *value = NULL;
 374
 375         if (!ctx->pctx->section) {
 376                 ctx->pctx->byte = *str - ctx->pctx->buf;
 377                 ctx->pctx->reason = "option command found before the first section";
 378                 UCI_THROW(ctx, UCI_ERR_PARSE);
 379         }
 380         /* command string null-terminated by strtok */
 381         *str += strlen(*str) + 1;
 382
 383         UCI_TRAP_SAVE(ctx, error);
 384         name = next_arg(ctx, str, true);
 385         value = next_arg(ctx, str, true);
 386         assert_eol(ctx, str);
 387         uci_add_option(ctx->pctx->section, name, value);
 388         UCI_TRAP_RESTORE(ctx);
 389         return;
 390
 391 error:
 392         if (name)
 393                 free(name);
 394         if (value)
 395                 free(value);
 396         UCI_THROW(ctx, ctx->errno);
 397 }
 398
 399
 400 /*
 401  * parse a complete input line, split up combined commands by ';'
 402  */
 403 static void uci_parse_line(struct uci_context *ctx)
 404 {
 405         struct uci_parse_context *pctx = ctx->pctx;
 406         char *word, *brk;
 407
 408         for (word = strtok_r(pctx->buf, ";", &brk);
 409                  word;
 410                  word = strtok_r(NULL, ";", &brk)) {
 411
 412                 char *pbrk;
 413                 word = strtok_r(word, " \t", &pbrk);
 414
 415                 switch(word[0]) {
 416                         case 'p':
 417                                 if ((word[1] == 0) || !strcmp(word + 1, "ackage"))
 418                                         uci_parse_package(ctx, &word);
 419                                 break;
 420                         case 'c':
 421                                 if ((word[1] == 0) || !strcmp(word + 1, "onfig"))
 422                                         uci_parse_config(ctx, &word);
 423                                 break;
 424                         case 'o':
 425                                 if ((word[1] == 0) || !strcmp(word + 1, "ption"))
 426                                         uci_parse_option(ctx, &word);
 427                                 break;
 428                         default:
 429                                 pctx->reason = "unterminated command";
 430                                 pctx->byte = word - pctx->buf;
 431                                 UCI_THROW(ctx, UCI_ERR_PARSE);
 432                                 break;
 433                 }
 434         }
 435 }
 436
 437 /* max number of characters that escaping adds to the string */
 438 #define UCI_QUOTE_ESCAPE        "'\\'"
 439
 440 /*
 441  * escape an uci string for export
 442  */
 443 static char *uci_escape(struct uci_context *ctx, char *str)
 444 {
 445         char *s, *p, *t;
 446         int pos = 0;
 447
 448         if (!ctx->buf) {
 449                 ctx->bufsz = LINEBUF;
 450                 ctx->buf = malloc(LINEBUF);
 451         }
 452
 453         s = str;
 454         p = strchr(str, '\'');
 455         if (!p)
 456                 return str;
 457
 458         do {
 459                 int len = p - s;
 460                 if (len > 0) {
 461                         if (p + sizeof(UCI_QUOTE_ESCAPE) - str >= ctx->bufsz) {
 462                                 ctx->bufsz *= 2;
 463                                 ctx->buf = realloc(ctx->buf, ctx->bufsz);
 464                                 if (!ctx->buf)
 465                                         UCI_THROW(ctx, UCI_ERR_MEM);
 466                         }
 467                         memcpy(&ctx->buf[pos], s, len);
 468                         pos += len;
 469                 }
 470                 strcpy(&ctx->buf[pos], UCI_QUOTE_ESCAPE);
 471                 pos += sizeof(UCI_QUOTE_ESCAPE);
 472                 s = p + 1;
 473         } while ((p = strchr(s, '\'')));
 474
 475         return ctx->buf;
 476 }
 477
 478
 479 /*
 480  * export a single config package to a file stream
 481  */
 482 static void uci_export_config(struct uci_package *package, FILE *stream)
 483 {
 484         struct uci_context *ctx = package->ctx;
 485         struct uci_section *s;
 486         struct uci_option *o;
 487
 488         fprintf(stream, "package '%s'\n", uci_escape(ctx, package->name));
 489         uci_foreach_entry(section, &package->sections, s) {
 490                 fprintf(stream, "\nconfig '%s'", uci_escape(ctx, s->type));
 491                 fprintf(stream, " '%s'\n", uci_escape(ctx, s->name));
 492                 uci_foreach_entry(option, &s->options, o) {
 493                         fprintf(stream, "\toption '%s'", uci_escape(ctx, o->name));
 494                         fprintf(stream, " '%s'\n", uci_escape(ctx, o->value));
 495                 }
 496         }
 497         fprintf(stream, "\n");
 498 }
 499
 500 int uci_export(struct uci_context *ctx, FILE *stream, struct uci_package *package)
 501 {
 502         UCI_HANDLE_ERR(ctx);
 503         UCI_ASSERT(ctx, stream != NULL);
 504
 505         if (package) {
 506                 uci_export_config(package, stream);
 507                 goto done;
 508         }
 509
 510         uci_foreach_entry(package, &ctx->root, package) {
 511                 uci_export_config(package, stream);
 512         }
 513 done:
 514         return 0;
 515 }
 516
 517 int uci_import(struct uci_context *ctx, FILE *stream, const char *name, struct uci_package **package)
 518 {
 519         struct uci_parse_context *pctx;
 520
 521         /* make sure no memory from previous parse attempts is leaked */
 522         uci_file_cleanup(ctx);
 523
 524         pctx = (struct uci_parse_context *) uci_malloc(ctx, sizeof(struct uci_parse_context));
 525         ctx->pctx = pctx;
 526         pctx->file = stream;
 527
 528         /*
 529          * If 'name' was supplied, assume that the supplied stream does not contain
 530          * the appropriate 'package <name>' string to specify the config name
 531          * NB: the config file can still override the package name
 532          */
 533         if (name)
 534                 pctx->name = name;
 535
 536         while (!feof(pctx->file)) {
 537                 uci_getln(ctx, 0);
 538                 if (pctx->buf[0])
 539                         uci_parse_line(ctx);
 540         }
 541
 542         if (package)
 543                 *package = pctx->package;
 544
 545         pctx->name = NULL;
 546         uci_switch_config(ctx);
 547
 548         /* no error happened, we can get rid of the parser context now */
 549         uci_file_cleanup(ctx);
 550
 551         return 0;
 552 }
 553
 554 int uci_load(struct uci_context *ctx, const char *name, struct uci_package **package)
 555 {
 556         struct stat statbuf;
 557         char *filename;
 558         bool confpath;
 559         FILE *file;
 560
 561         UCI_HANDLE_ERR(ctx);
 562         UCI_ASSERT(ctx, name != NULL);
 563
 564 ignore:
 565         ctx->errno = 0;
 566
 567         switch (name[0]) {
 568         case '.':
 569         case '/':
 570                 /* absolute/relative path outside of /etc/config */
 571                 filename = (char *) name;
 572                 confpath = false;
 573                 break;
 574         default:
 575                 filename = uci_malloc(ctx, strlen(name) + sizeof(UCI_CONFDIR) + 2);
 576                 sprintf(filename, UCI_CONFDIR "/%s", name);
 577                 confpath = true;
 578                 break;
 579         }
 580
 581         if ((stat(filename, &statbuf) < 0) ||
 582                 ((statbuf.st_mode &  S_IFMT) != S_IFREG)) {
 583                 UCI_THROW(ctx, UCI_ERR_NOTFOUND);
 584         }
 585
 586         file = fopen(filename, "r");
 587         if (filename != name)
 588                 free(filename);
 589
 590         if (!file)
 591                 UCI_THROW(ctx, UCI_ERR_IO);
 592
 593         return uci_import(ctx, file, name, package);
 594 }
 595